Chemical Pathology 16 - Hypoglycaemia

Question 1

How should hypoglycaemia be managed if the patient is alert and oriented?

Answer 1

Juice and a sandwich

Continuous monitoring and treat cause

Question 2

How should hypoglycaemia be managed if the patient is drowsy, but not unconscious?

Answer 2

Bucchal glucose (this bypasses 1st pass metabolism) 
Continuous monitoring and treat cause

Question 3

How should hypoglycaemia be managed if the patient is unconscious or has a reduced swallow reflex?

Answer 3

IV glucose 20%

Continuous monitoring and treat cause

Question 4

What are the possible symptoms of hypoglycaemia?

Answer 4

Adrenergic symptoms - tremors and sweating
Neuroglycopaenic symptoms - somnolence and confusion
None - in some type 1 diabetic

Question 5

What is the body’s physiological response to hypoglycaemia, and which of these responses if the first?

Answer 5

1st - reduced insulin

Then catecholamine release (ACTH, cortisol and GH increase, causes adrenergic symptoms) and increased glucagon

Question 6

Recall the effects of glucagon

Answer 6

Directly: 
1. Decreases peripheral glucose uptake
2. Increases glycogenolysis
3. Increases gluconeogenesis in the liver and kidneys 
4. Increases lipolysis 
This then leads to: 
1. Increased glucose 
2. Inceased free fatty acids 
Fatty acids undergo beta oxidation --> ketones

Question 7

What is the best measure of glucose?

Answer 7

Venous glucose (way better than capillary)

Question 8

Recall 6 differentials for the cause of hypoglycaemia in a NON-diabetic patient

Answer 8

1. Critically unwell pt
2. Organ failure
3. Hyperinsulinism
4. Drugs
5. Extreme weight loss
6. Factitious

Question 9

Recall 5 differentials for the cause of hypoglycaemia in diabetic patients

Answer 9

1. Medications - these iatrogenically reduce glucose
2. Inadequate CHO intake (T1D especially)
3. Impaired awareness (eg EtOH)
4. Exercise
5. In presence of autoimune conditions eg Addissons

Question 10

What class of drug is gliclazide?

Answer 10

Sulphonylurea

Question 11

Which 2 classes of oral diabetic drug are most likely to cause a hypo?

Answer 11

Sulphonylureas (eg gliclazide)

GLP-1 agents

Question 12

Recall 3 non-diabetes drugs that can cause a hypo

Answer 12

Beta blockers (impair adrenergic response so have impaired awareness of symptoms)
Salicylates - impair regulation of glucose
Alcohol

Question 13

In a neonate with hypoglycaemia but no ketones, what is the likely diagnosis?

Answer 13

Inborn error of fatty acid metabolism

Question 14

Recall 3 possible causes of hyperinsulinaemic hypoglycaemia

Answer 14

1. Insulinoma (islet cel tumour)
2. Drugs (eg insulin/ sulphonylurea)
3. Islet cell hyperplasia

Question 15

Recall 3 causes of islet cell hyperplasia in the neonate

Answer 15

1. Infant of a diabetic mother
2. Beckworth Wiedmann syndrome
3. Nesidioblastosis

Question 16

How can non-islet cell tumours cause hypoglycaemia?

Answer 16

This is a RARE case - most likely to occur in mesothelioma/ carcinoma of the lung
These tumours secrete ‘big IGF-2’ (paraneoplastic syndrome) which binds to both IGF-1 and insulin receptors
In this case, insulin and C peptide will both be low

Question 17

What are the 4 first basic biochemical tests that should be done in hypoglycaemia investigation?

Answer 17

1. Glucose
2. Insulin
3. C peptide
4. Drug screen

Question 18

Recall 5 advanced biochemical tests that can be used in investigating a hypoglycaemia

Answer 18

Ketones and FFAs
IGF studies
Ammonia
Lactate
Inborn error of metabolism screen